Snooze scientists track sleep debt

MUMBAI: A self-confessed rock-around-the-clocker, Disha says she freaks out when she thinks of spending such a large chunk of her life in sleep.
If she could, she would gladly squeeze some more life out of the few hours she has for sleep in her frenetic schedule.
However, scientists say people like Disha who think they can function well on very little sleep may be deceiving themselves.
Recent research by the University of Pennsylvania has found that even folks who regularly got six solid hours of sleep every night in a twoweek period, began to do as badly on brain function tests as those subjects who hadn''t slept at all for two consecutive days.
The scientists studied the neurophysiological patterns of 48 subjects between the ages of 21 and 38 who were assigned to receive either four, six or eight hours of sleep for 14 days or forced to go without sleep for three days.
When they were awake, the subjects were given neuropsychological tests. To no one''s surprise, the scientists found that performance on these tests steadily deteriorated as sleep deprivation built up, to the point where those who slept for four or six hours began to do as badly as those who had had no sleep at all.Moreover, even participants who reported feeling only slightly sleepy did quite poorly on their neuropsychological scores.
This dispels the myth that people can do with less sleep, that they can adapt to it, get used to it and fail to suffer the consequences, Dr Hans P.A. Van Dongen, an assistant professor of sleep and chronobiology at Penn who worked on the study, told ''The Philadelphia Inquirer''.
He said people who cheat on their sleep night after night eventually get slapped with a ''sleep debt'', which affects virtually every function requiring alert attention, quick reaction time and seamless working memory. It''s important to devote time to sleep, he warned, even if means using weekends to discharge the sleep debt that one has accumulated during the week by working late.
The research reinforces earlier findings on the vital role played by sleep in learning. For instance, scientists at the Harvard Medical School showed that those who opted for all-night crammers could not have chosen a poorer way to prepare for exams.
They demonstrated that our memory of newly learned stuff improves only after sleeping at least for six to eight hours. This was because the sort of sleeping one does at the beginning of a night''s sleep (characterised by slow waves) and that at the end are different, and both seem to be needed for efficient learning via strengthening of neural connections.
Some scientists warn that even those who studied hard all week and then stayed up all night partying on the weekend could stand to lose as much as 30 per cent of what they had learned during the week.
Similarly, scientists at the University of California in San Diego have shown that following sleep deprivation, brain activity actually gets altered —parts of the brain such as the frontal lobe critical for decision-making, seemed severely handicapped when the subject was seriously sleep deprived.
Lack of sleep also seems to cause differences in the way we actually think.
This may be because sleepdebited zombies may be using some of their vital resources to fight off the need for sleep. Other experts say the Penn study findings drive home the point that sleep-deprived people often are not aware of their deficits.
According to a poll conducted by the National Sleep Foundation, for example, at least 63 per cent of Americans today do not get eight hours of sleep every night.
They sleep less than they did five years ago not only because they are working longer but because an increasingly round-theclock society allows people to eat out, shop, surf the channels or chat on the net at any hour of the day or night.